1. Field
The present disclosure relates generally to aircraft and in particular to a method and apparatus for managing air quality in an aircraft. Still more particularly, the present disclosure relates to a method and apparatus for providing personal ventilation in an aircraft.
2. Background
Cabin air systems, in currently available aircraft, are designed to provide a safe and comfortable cabin environment at cruising altitudes. These cruising altitudes may reach upwards of 40,000 feet. At these altitudes, the aircraft cabin is pressurized to enable the passengers and crew to breathe normally. Air enters a passenger area from overhead distribution outlets that run the length of the passenger cabin.
These outlets may be designed to generate circular airflow patterns within the cabin. Air may be exhausted through air returns located in sidewalls near the floor of the cabin. These grills may be located along the length of the cabin and on both sides of the cabin. Air may be supplied and exhausted from the passenger area on a continuous basis.
The air supplied to the cabin contains a mixture of re-circulated air from within the passenger cabin and air from outside of the aircraft. To increase the efficiency of modern jet aircraft and comfort of the aircraft cabin, it may be desirable to increase the ratio of recycled/re-circulated air to outside air. In the early days of jet travel, the aircraft cabin was around 100 percent outside air.
Today, the mix of outside air and re-circulated air may be around 50 percent outside air and around 50 percent re-circulated air. As a result of this change, there was a small increase in humidity levels. However, there may be a concern that an increased level of contaminants may be present in modern jet aircraft cabins due to the increased levels of re-circulated cabin air. Additionally, this increased level of contaminants may decrease passenger enjoyment.
One solution may involve increasing the total airflow to dilute contaminants utilizing high-efficiency particulate air (HEPA) filters for the entire passenger cabin. Other solutions may involve airflow balancing in the cabin to minimize airflow in the fore and aft directions. Further, ultraviolet lights may be included within the aircraft ventilation ducts. The ultraviolet lights may be used to inactivate airborne bacteria and/or viruses.
These systems may remove, dilute, and/or destroy contaminants from the cabin air as it circulates within the aircraft. In these examples, contaminants may include any undesirable particulate. For example, without limitation, a contaminant may be bacteria, viruses, pollen, dust, or other undesirable items. Although these systems may clean air within the passenger cabin, the different advantageous embodiments recognize a limitation with these types of solutions.
Accordingly, there is a need for a method and apparatus for ventilating air in a passenger cabin of an aircraft which overcomes the limitations described above.